A suction attachment of the kind mentioned in the opening paragraph is known from European Patent 0 316 849. The known suction attachment has an elongate underpressure chamber and an inner chamber which is also elongate and which extends through a central plane of the underpressure chamber, the suction opening of the underpressure chamber and the orifice of the inner chamber extending in one plane. The spray member of the known suction attachment has a distributor chamber for the cleaning liquid positioned inside the inner chamber, the feed channel for the cleaning liquid issuing into this distributor chamber. The distributor chamber is bounded by a T-shaped closing strip which extends parallel to the suction opening and whose cheeks are provided with a regular pattern of incisions. The distributor chamber is filled with the cleaning liquid through the feed channel. When the distributor chamber is substantially full, a continuous and sufficient flow of the cleaning liquid takes place through the incisions of the closing strip and the orifice of the inner chamber towards a surface to be cleaned under the influence of a liquid pressure built up in the distributor chamber. The cleaning liquid is distributed substantially uniformly over the orifice of the inner chamber and the surface to be cleaned owing to the use of the said closing strip.
A disadvantage of the known suction attachment is that a continuous and sufficient flow of the cleaning liquid is achieved only when the distributor chamber of the spray member is substantially full. Owing to the presence of the cleaning liquid in the distributor chamber, the weight to be lifted by a user during moving of the suction attachment and the pushing force to be exerted by the user on the suction attachment during shifting of the suction attachment over the surface to be cleaned are comparatively great, whereby the handling ease of the suction attachment is adversely affected. In addition, the known suction attachment drips after use because there is still cleaning liquid in the distributor chamber which flows out gradually along the closing strip to the exterior.